Fig 2: RRM2 knockdown was verified by real-time PCR and Western blot. Control cells were transfected with lentiviral vectors containing non-silencing shRNA (Lenti-shCtrl), and experimental cells were transfected with lentivirus-mediated RRM2 shRNA (Lenti-shRRM2-1 and Lenti-shRRM2-2). (A) RRM2 mRNA expression in Lenti-shRRM2 cells was significantly lower than in Lenti-shCtrl cells of 93T449, 94T778, and SW872 cells using real-time PCR (**P<0.01). (B) The downregulation of RRM2 protein expression was confirmed by Western blot.

Fig 3: Downregulation of RRM2 inhibited the proliferation of RLPS cells. (A) The results of CCK-8 assay showed that the downregulation of RRM2 inhibited RLPS cell proliferation significantly in 93T449, 94T778, and SW872 cells (***P<0.001, **P<0.01). (B) and (C) Knockdown of RRM2 expression reduced colony-forming capacity of the three cell lines (***P<0.001, **P<0.01).

Fig 4: Apatinib inhibited RRM2 and TYMS-related pathways in liposarcoma. (A) Heatmap of top representative DEGs associated with Apatinib treatment in SW872 cell lines. (B) KEGG pathway enrichment analysis indicated that Apatinib could inhibit liposarcoma proliferation through p53 signaling, DNA replication, and other important signaling pathways. (C) GO analysis showed that Apatinib application affected mainly organelle fission, DNA replication, mitosis, cell cycle, and other important processes. (D) Western blotting (WB) showed that Apatinib downregulates RRM2, p-PI3K, p-AKT, and p-mTOR expression in liposarcoma cells compared with control group. (E) WB indicating that Apatinib downregulates TYMS, p-STAT3, and PD-L1expression in liposarcoma cells compared with control group.

Fig 5: Protein levels of cellular nucleotide biosynthesis enzymes in irradiated senescence-enriched human glioblastoma cell lines and non-irradiated controls. Human U87 and ED501 glioblastoma cell lines were either non-irradiated (0 Gy) or treated with a radiation dose of 10 Gy. Then 7 days later, whole cellular lysates were isolated and analyzed by immunoblotting. Representative images of immunoblots (left panels) and quantified band signals (arbitrary units, A.U.; right panels) show expression of nucleotide biosynthesis enzymes: (A) thymidine kinase 1 (TK1); (B) ribonucleotide reductase regulatory subunit M2 (RRM2); (C) p53 inducible small subunit of ribonucleotide reductase (p53R2). β-actin or β-tubulin were used as loading controls. Data information: data represent three independent experiments. The quantified band signal was determined by normalizing the probed signal with a loading control signal. For (A-C; right panels), mean ± SEM is shown, and unpaired t-test was used to determine significance (* p < 0.05; ** p < 0.01). The uncropped immunoblots are shown in Supplementary Material File S1.